(a) The pupil is approximately one-third the size of the eye. It dilates and contracts according to intensity of light and distance of object being focused. The pupil should be black and brilliant.
(b) A thin visible muscle (often called the scouting sight) should completely encircle the pupil. This muscle dilates and contracts the pupil. A portion of the muscle may be of a darker shade and located either at the front or lower front of the pupil. This muscle should be prominent in at least one of the birds selected for breeding to produce a higher percentage of dependable birds. If pigeons which do not possess this muscle, or which have only a small portion of it visible, are to be used for breeding purposes, they should be mated to pigeons having a muscle which is more prominent even though it may not completely surround the pupil.
(c) The iris determines the color of the eye. It should be well blended and possess the brilliance denoting life and observance. Pigeons possessing faded or weak eyes are not desirable for breeding purposes.
Splashed birds often possess a “bull eye” which has an iris of a solid, dark purplish-brown color. When this color appears only on a part of the iris, the bird has a splashed eye. It is hard to detect the muscle surrounding the pupil when the “bull eye” is present.
The color of the iris may be maroon, ruby-red, rose, pink, walnut, chestnut-brown, orange, yellow-orange, carrot, violet, grayish white, or pearl. When the iris consists of one color only, it will be considered a “full eye.” Two colors may occasionally be present in the iris, such as red and yellow, orange and yellow, and so forth. The two colors should be well blended in any case. “Full eyes” and “two-colored eyes” are both satisfactory for breeding purposes. Mated birds should have irises of similar shades.
The outer part of the iris is normally darkest; the color diminishes toward the center of the eye. This coloring is more pronounced when the birds are in top condition.
(d) The thin line circumscribing the iris should be extremely dark and very distinct.
(e) The remainder of the eyeball should be dark and well covered by the cere. The bird is said to have an “open eye” when the portion of the eyeball which should be covered by the cere is visible. Birds with open eyes are undesirable for breeding.
(f) The upper and lower lids are a part of the eye cere. A third lid which is a transparent membrane frees the eye from foreign material. The blinking of the third lid can scarcely be detected when the pigeons are in perfect health.
(3) Size and temperament. Medium-sized pigeons are most desirable and birds should be mated to attain this uniform size. Birds being mated to breed stock for pigeon communication should be calm and easy going, not high-strung. Nervous or excitable birds should never be mated.